1. Field of the Invention
The present invention relates to a radiation imaging apparatus, a control method, and a storage medium storing a computer program.
2. Description of the Related Art
There is known a radiation imaging apparatus that captures a radiation image based on detection of radiation (e.g., X-rays) having passed through an object. For example, the radiation imaging apparatus captures an image of an imaging target region, such as a digestive tract, by radiation. The radiation imaging apparatus is widely used not only for inspection during medical treatment but also for routine medical checkup.
There are various types of radiation imaging apparatuses. For example, Japanese Patent Application Laid-Open Nos. 2005-027806 and 2010-194057 discuss apparatuses that, while positioning an object placed on a top board of a bed between an X-ray generation apparatus and an X-ray detection apparatus attached to both ends of a support member referred to as a C arm, radioscopically view and capture an image of the object. X-rays emitted from the X-ray generation apparatus pass through the object to enter the X-ray detection apparatus. The X-ray detection apparatus converts the X-rays having passed through the object into an electric signal. By performing such an operation under a predetermined X-ray irradiation condition, the captured image or the radioscopically viewed object can be displayed on a monitor in real time.
In the case of the X-ray imaging apparatus, operations concerning radioscopical viewing and imaging performed by an operator are roughly classified into the steps of: (1) positioning carried out while performing radioscopical viewing; (2) diagnosis in a radioscopically viewed state (checking of an imaging target region); and (3) imaging of a positioned region.
In the step (1) “positioning carried out while performing radioscopical viewing”, the positioning is performed so that the imaging target region can be displayed with a desired size at an appropriate position (e.g., a center position) of the monitor. During the positioning, the operator moves at least one of the X-ray generation apparatus, the X-ray detection apparatus, and the top board.
In other words, since the operator moves such a unit during the positioning, the image (observed image) displayed on the monitor moves. On the other hand, in the step (2) “diagnosis in a radioscopically viewed state (checking of an imaging target region)”, the operator does not perform any positioning operation. The position of the observed image on the monitor is in a fixed state.
Then, when the operator visually confirms the imaging target region, the step (3) “imaging of a positioned region” is performed under the predetermined X-ray irradiation condition. During X-ray imaging, the operation steps of (1) to (3) are repeated.
Generally, in a medical modality that uses X-rays, how to shorten a time for radioscopical viewing and imaging or how to reduce an X-ray exposure dose of the object is an important control item and a research item.
For example, in the “positioning carried out while performing radioscopical viewing”, if an image displayed on the monitor moves on the monitor interlockingly with only the operator's positioning operation, the positioning operation can be continued without any radioscopical viewing, and the X-ray exposure dose of the object can be reduced.